Controlling means for hydraulic motors



Oct. 5, 1943.

v vc.o.'1. MQNTELlus I 2,331,218 comonme Mms ronxlwmumc mons Filed aaron 1v. 1959 Patented Oct. 5, 1943l ooNTnoLLlNG MEANS Fon HYDRAULIC f f- Mo'rons v vcan loscar, 'rol-sten Monteuu's, stockhblm,

Stockholmg Sweden Application March 17, 1939, Seal No. 262,575

Sweden, assignor to Aktiebolaget Imc-Industri,

In Sweden September 5, 1938 K 2 Claims.

'l-For the control of the speed of lhydraulic motors therel isgenerally made use =of a valve,

which, in case of the hydraulic motor being driven by a'puznp-having a constantcapacity, permits a certain quantity of liquid beingby-passed without-entering the motor. In case of the lmotor being ldriveriby pressure liquid from van accumulator or pressure conduit, thevalve is so adjusted (Cl. 60m-53).`

Threaded into the other end of the valve rnernf` ber I3 isa screw I5 having ashaft Ila, which is y connected to the shaft I`| of a direct ,current electric control motor I8 by means of,'a coupling that the -quantityof liquidcaused to -fiow to the hydraulic' motor corresponds tothe desired number'of revolutions.'v .In :bothcasesthe said simple' means comprising.y hand-operated Vvalve is not entirely satisfactory, in as much as the number of revolutions of the motor `varies to a great extentf.-.atv ,variations of Ythe load, .and for such reason a satisfactory speed control often cannot be obtained.

The present invention has for itsobject to improve the speed control of such motors and consists essentially in this that the valve device, which, by regulating the quantity of liquid passing through the said motors, directly controls the speed or the direction of rotation of the motors, is arranged to be adjusted through the difference of speed of a shaft driven bythe hydraulic motor and a second shaft driven by a control motor.

In the annexed drawing an embodiment `of a control means according to this invention is shown. Fig l shows diagrammatically the control means as a whole. Figs. 2 and 3 are axial sections of the control valve on an enlarged scale, showing the valve in two different positions.

Fig. 4 shows a modification of the embodiment according to Fig. 1, some parts being broken away for the sake of simplicity.

Referring to Fig. 1, I designates a pump, which is driven at a constant number of revolutions by an electric motor 2. The pressure pipe of the pump is designated by 3 and its suction pipe by 4. The pressure pipe 3 opens centrally in a valve housing 5, while two branch pipes. 6 and 'I of the suction pipe 4 are connected at the ends of the valve housing. Connected to the said housing are further two pipes 8 and 9, which I6. The field winding ofthe motor is connected directly to the direct current mains, while the direction and speed of the rotor is controlled, by an adjustable resistance I9 and a sliding contact 20 cooperating-therewith.

If the contact 20 be placed at a, the motor :runs

at full speed in. the one direction, while the speed?. is reduced whenv movingy the contactinihe direction towards the point'o. K At further` displace` ing -thevcontactfrom o` in the direction towards. b the directionof the-rotation is` reversed,` and, at b the ymotor runs at fullspeed inthe reverse direction. g

If it be assumed to begin with that the hydraulic motor I0 and the electric control motor I8 run at the same speed in the same direction, the valve member I3 takes up a certain determined position in the valve housing 5, and the pressure liquid from the pump I flows through the pressure pipe 3 to the valve housing and from there (depending on the position of the valve member I3) for instance through the pipe 9 to the hydraulic motor I 0 and then through the pipe 8, the valve housing 5, the branch pipe B and the suction pipe 4 back to the pump I (the valve position shown in Fig. 2). If now the speed of the control motor I8`- be changed, a relative rotary movement will take place between the shaft I I of the hydraulic motor with the shaft IIa and the valve member I3 on the one hand and the shaft I'I of the control motor with the shaft Ila and the screw I5 on the other hand, and thus an axial displacement of the valve member will take place due to the screw connection. Ii the speed of the control motor is reduced, thevalve member I3 will be moved in the direction from the right towards the left in Fig. 2, so that part of the pressure liquid entering into the valve housing through the pressure pipe 3 will pass directly to the branch f pipe 1 and through the suction pipe 4 back to the pump I, resulting in a reduced liquid supply to the hydraulic motor and, as a consequence, in a reduced speed of said motor. An increase of the speed of the control motor I8 will cause a displacement of the valve member in the opposite direction, resulting in an increased liquid supply to the hydraulic motor and an increased speed thereof. When the speed of the two motors is equal, the valve member will again take up a determined position.

'If, on'th'e other hand. due to an increase or a decrease of the load of the hydraulic motor, the speed of said motor should be reduced or increased, respectively, the valve displacements will take place in the reversed directions. that is to say, the valve will be adjusted for an increased or decreased liquidsupply, respectively, until the Y speeds of the two motors will again.' be equal. 1-

If the direction of rotation of the control moy tor I8 be reversed by moving the sliding contact Z to a position between o and b or at b, the .i

valve member I3 will be moved to theposition shown in Fig. 3. in which thevliquid'from therv pressure pipe 3 will pass from the valve housing 5 through the pipe 8 to the hydraulic motorjltl housing and then through the branch pipe 1 to Further, it is evident that in the embodimenty according to Figs. 1 to 3 the shaft lla may be connected to the valve body Il by means o! a threaded connection and the shaft 11a by means of a key-connection.

An arrangement according to the invention may be applied for instance to paper-making machines, reversible rolling-mills, tower-clocks and the like.

What I claim as new and Vdesire to secure by "Letters Patent of the United States of America is:

1. In combination, a pressure liquid sourcel at least' one hydraulic motor in communication l with said'prcssure source, a valve device in said `l1&5 and from there through the pipe'tothcvalvc the suction pipe I of the pump. iLThus; also lthe f direction of movement of the hydraulic motor,

will be reversed. For the rest the controlling operations take place in the manner described communication controlling the ow oi' liquid through said hydraulic motor, an electric control motor, a shaft driven by said hydraulic motor, a Asecond shaft driven by said electric control 1, motor, connections between each of said shafts and said valve device operative, at relative rotary movements of said shafts, to bring about adjust ments ofthe valve device to cause adjustments of the speed of the hydraulic motor to that of the electric control motoran electric circuit including said electric control motor and having a constant terminal voltage, and a potentiometer in said circuit operative to supply a controllable voltage to the armature of the, electric control motor tofvary the speed thereon 2. A device according to'claim 1,-characterizcd by the'valve device and the poteniometer being does thecontrol motor, which is connected to the.

valve'bodyli exactly inthe samewayas shown inFigmltoS. u

made to reverse thedirection o! rotation o! the hydraulic'motor andthe control motor, respectively. vf Y I v l ,CARL oscsa 'roas'rau MoN'reuUs. 

